The present invention relates to a rotary compressor comprising a sealed container in which a driving element and a rotary compression element driven by the rotation of this driving element are provided, and a manufacturing method of the rotary compressor.
Heretofore, this type of rotary compressor has comprised a sealed container in which a driving element and a rotary compression element driven by a rotary shaft of this driving element are included. The rotary compression element is constituted of a cylinder, a roller fitted into an eccentric portion formed on the rotary shaft to eccentrically rotate in the cylinder, a vane which abuts on the roller to partition the inside of the cylinder into a low pressure chamber side and a high pressure chamber side, a support member which closes the open surface of the cylinder and which has a bearing of the rotary shaft, and a discharge muffler chamber provided opposite to the position of the cylinder of the support member. Moreover, the discharge muffler chamber is connected to the high pressure chamber side in the cylinder via a discharge port, and in the discharge muffler chamber, a discharge valve is provided which openably closes the discharge port.
Moreover, when the driving element is driven, a low-temperature low-pressure refrigerant gas is sucked into the low pressure chamber side of the cylinder through a suction passage, and compressed by the operation of the roller and the vane. When the refrigerant gas in the cylinder is compressed to reach a predetermined pressure by the operation of the roller and the vane, the discharge valve is pushed upwardly by such a pressure of the refrigerant gas to connect the high pressure chamber side of the cylinder to the discharge muffler chamber via the discharge port. In consequence, the refrigerant gas on the high pressure chamber side of the cylinder is discharged from the high pressure chamber side of the cylinder to the discharge muffler chamber through the discharge port. The high-temperature high-pressure refrigerant gas discharged to the discharge muffler chamber is discharged into the sealed container, and then discharged to the outside through the sealed container (e.g., see Japanese Patent Application Laid-Open No. 2007-56860 (Patent Document 1)).
In addition, when such a rotary compressor is mounted in an air conditioner, the improvement of a performance from a rated load operation to an intermediate load operation has become necessary owing to an energy saving regulation in recent years. FIG. 9 is a diagram showing the pressure transition in the rated load operation and the intermediate load operation at the rotation angles of a conventional rotary compressor. In FIG. 9, a broken line shows the pressure transition during the rated load operation in the conventional compressor, and a solid line shows the pressure transition during the intermediate load operation in the conventional compressor. As shown in FIG. 9, the intermediate load operation has operating conditions on which a condensation temperature is low as compared with the rated load operation. Therefore, in the conventional rotary compressor, the pressure in the cylinder rapidly reaches a high pressure during the intermediate load operation, and hence the discharge valve is opened in an early stage. Moreover, this opened discharge valve remains opened until the roller passes through the discharge port. In such a state where the discharge valve is opened, the pressure on the high pressure chamber side in the cylinder has the highest state, and a high pressure load is applied to the roller in the cylinder and the rotary shaft, whereby a problem occurs that the performance of the compressor is accordingly influenced.